DNA

Question 1

Semi-conservative replication

Answer 1

The process by which the two original strands of a DNA molecule separate and each is used as a template to form a new complementary strand.

Question 2

The four base pairs of DNA + one of RNA

Answer 2

• Adenine
• Guanine
• Cytosine
• Thymine
• Uracil (RNA)

Question 3

Complementary base pairs

Answer 3

A-T
G-C
Work because they allow consistent distance between backbones

Question 4

Purines

Answer 4

Larger

• Adenine
• Guanine

Question 5

Pyrimidines

Answer 5

Smaller

• Thymine
• Cytosine
• Uracil (RNA)

Question 6

Hydrogen bonds between complementary base pairs

Answer 6

A-T two hydrogen bonds

C-G three hydrogen bonds

Question 7

During which stage of cell cycle

Answer 7

Interphase S-Phase

Question 8

DNA related enzymes

Answer 8

• Helicase
• Single-strand binding proteins
• RNA Primer
• DNA Polymerase
• DNA Ligase

Question 9

Steps to DNA replication

Answer 9

• Helicase brakes hydrogen bonds between complementary base pairs to separate the two strands
• Single-strand binding proteins bind to strands to keep them apart
• RNA Primer adds a primer that allows the DNA polymerase to work
• free floating nucleoside triphosphates use their extra phosphate groups to power DNA polymerase, this binds the backbones of the new nucleotides together in a 5’ to 3’ direction
• on the leading strand, only one primer is needed and then replication can begine from the origin of replication towards the helicase
• on the lagging strand the polymerase must work away from the replication fork. because of this, synthesis is discontinuous and each new segment is called an Okasaki fragment. each new OF must be started with a new DNA Primer.
• DNA Ligase then joins the Okasaki fragments together
• DNA polymerase proofreads the DNA molecule

Question 10

Gene

Answer 10

a length of DNA that codes for a specific characteristic

Question 11

triplet code

Answer 11

three base pairs that code for a specific amino acid

Question 12

Introns

Answer 12

parts of a DNA strand that control what is done to the dna and reading of the dna, for example, when transcription should start or what genes are turned off or on.

Question 13

repetitive sequences

Answer 13

repeating length of DNA that has no apparent use

Question 14

steps to transcription

Answer 14

-gene is found
-rna polymerase opens up strand
-reads antisense strand in a 3’ to 5’ direction
-adds rna nucleotides 5’ to ‘3’ direction
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